STMicroelectronics LD1085V25

Overview

LD1085V25 from STMicroelectronics is a fixed-output 2.5 V, 3 A low-dropout linear voltage regulator in TO-220 package, featuring ±1% output tolerance at 25 °C, 1.3 V typical dropout at full load, internal thermal and current limiting, and operation from –40 °C to +125 °C. It powers microcontroller core rails, FPGA I/O banks, and industrial sensor signal chains requiring stable low-noise DC supply.

For engineers reviewing the LD1085V25 datasheet, LD1085V25 pinout, LD1085V25 application, or LD1085V25 equivalent, this page delivers verified electrical specs, thermal performance data, package mechanical dimensions, real-world use cases, and validated alternative parts - all grounded in ST's official production datasheet (DocID6738 Rev 27).

Technical Context

The LD1085V25 uses an NPN-based pass transistor architecture with on-chip reference trimming, enabling tighter output voltage accuracy (±1% at 25 °C) than legacy PNP regulators. Its quiescent current flows into the load rather than being wasted, improving efficiency under light loads.

It achieves stability with only a 10 µF output capacitor and supports adjustable configurations via the ADJ pin when used in its adjustable variant (LD1085V). Dropout voltage remains ≤1.5 V across –40 °C to +125 °C junction temperature and full 0–3 A load range.

Key Specifications

Pinout & Package

LD1085V25 is supplied in TO-220 package (3-pin, vertical mounting, metal tab connected to output). Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output (tab). Compatible with standard heatsink clips and PCB through-hole footprints per ST mechanical drawing BUHY'.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO regulator applications.

Compared with LM2940CT-2.5 and TLV1117-25CDCYR, LD1085V25 uniquely combines 3 A output, 1.3 V dropout, ±1% accuracy, and integrated thermal/current protection in TO-220 - making it the only drop-in solution for industrial 2.5 V high-current rails requiring robustness and precision.

Availability

LD1085V25 is available at Aetrix Electronics and suitable for industrial automation controllers, medical diagnostic sensors, FPGA-based edge computing platforms, and automotive body electronics requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LD1085V25 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and power management applications.

LD1085V25 belongs to ST's high-current LDO regulator product line, engineered specifically for industrial and embedded systems demanding precision, reliability, and thermal resilience in harsh environments.

FAQ

What is the minimum input voltage required for LD1085V25 to maintain regulation at 3 A?

The LD1085V25 requires a minimum input voltage of 3.8 V to sustain 2.5 V output at 3 A load, based on its guaranteed 1.5 V maximum dropout voltage (VI ≥ VO + Vd = 2.5 V + 1.5 V). At lighter loads, dropout decreases - e.g., ~0.8 V at 1 A - allowing lower input voltages while maintaining regulation.

Can LD1085V25 be used in adjustable mode?

No - LD1085V25 is a fixed-output variant with internal resistor network setting 2.5 V. The adjustable version is LD1085V (no suffix), which uses an external resistor divider on the ADJ pin. Pinout and package are identical, but internal topology differs; substituting LD1085V25 for LD1085V will yield unregulated 2.5 V output regardless of external resistors.

Is a heatsink mandatory for LD1085V25 at full 3 A load?

Yes - with R_thJC = 3 °C/W and R_thJA = 50 °C/W (TO-220), dissipating 3.75 W (at 5 V input, 2.5 V output, 3 A) raises junction temperature by 187.5 °C above ambient without heatsinking. A heatsink reducing R_thJA to ≤20 °C/W is required to keep T_J ≤125 °C at 25 °C ambient.

Does LD1085V25 require an input capacitor?

Yes - ST recommends ≥10 µF low-ESR aluminum or tantalum capacitor at the IN pin to suppress input transients and ensure stability during line-step events. Ceramic capacitors alone are insufficient due to their ultra-low ESR; a 10 µF tantalum or 22 µF aluminum electrolytic is preferred for robustness against surge currents.